*Does a 600w lamp need a cool tube?*

Hello guys looking in,

Upgrading to a 600w i will be running 6 inch extraction fan, with a 4 inch inlet fan within a square meter tent and just under 2 meters high.


This tent will be within a room 6 meters by 3 meters with the use of an air con unit.

My million dollar question is this will it be enough to keep the temps down inside the tent to 26 c ?

Or in your experience of using a 600 w lamp given what i have above whats your opinion do i have no chance of keeping it cool enough ?? and will i need need to get a cool tube of hood etc

any advice appreciated if any has already tryed what i going to do, thanks KB

fire it up & see what kind of temps you get i did 2 grows [400w.hps] without a/c or cooled reflector if your a/c is up to the task you should be ok

if your a/c cools the room adequately then your grow tent should be cool enough without a cooltube or air cooled hood. however, with a cooltube of air cooled hood you can lower the light to within 6" of the plants, greatly increasing the efficiency of the lights.

desertrat said:

if your a/c cools the room adequately then your grow tent should be cool enough without a cooltube or air cooled hood. however, with a cooltube of air cooled hood you can lower the light to within 6" of the plants, greatly increasing the efficiency of the lights.

Click to expand...

Thanks guys for the replies, cool tubes get a bad press with regard to light spread and a cooled hood is prefered this i get from reading.

At the moment i have a serious heat problem so i'm going to deal with it so it seems from your replies with correct extraction and an ac i may be well be ok with the 600w.


As also said above fire it up see what temps i'm getting if it works fine great if not a cool hood i will get then...''

I have a couple 600's in easy cool 6" hoods. A 424 CFM fan sucking through a tall boy carbon filter and then pushing through both hoods keeps temps about 78F at 8" off the glass and the light distribution seems fine. They aren't COMPLETELY sealed though.. there is a bit of air leaking. Not enough to concern me, but if someone were to run CO2 it could be a concern. Just my 2 cents.

kathleen billy said:

Hello guys looking in,

Upgrading to a 600w i will be running 6 inch extraction fan, with a 4 inch inlet fan within a square meter tent and just under 2 meters high.


This tent will be within a room 6 meters by 3 meters with the use of an air con unit.

My million dollar question is this will it be enough to keep the temps down inside the tent to 26 c ?

Or in your experience of using a 600 w lamp given what i have above whats your opinion do i have no chance of keeping it cool enough ?? and will i need need to get a cool tube of hood etc

any advice appreciated if any has already tried what i going to do, thanks KB

Click to expand...

if you can keep the temps down in the mid 70's to high 70's then you do not need a cool tube. cool tubes are mainly for small are, air tight grow areas. if your in a big room and the heat can dissipate then you cool.

I wouldn't be able to without ducting. A 400W is my limit.

mygirls said:

if you can keep the temps down in the mid 70's to high 70's then you do not need a cool tube. cool tubes are mainly for small are, air tight grow areas. if your in a big room and the heat can dissipate then you cool.

Click to expand...

As it stands with my 400w and 4 inch extraction, the room temperature is 21 c but within the tent it's 39 c !

To be fair i have no inlet fan, i opened the tent and blow and cooling fan direct into it and got temps down to 25 c.


So i'm going to shorten the ducting run of the extraction which should improve that, as it's far too long 3 meters with two 45 degree bends not good.

I've learned i definately need a inlet fan and i will add the ac in the next week or so....''

Lets see if i can get the temps right with my 400w and the big changes above overwise i'm wasting my time with the thought of a 600w but that is my aim i will tackle this heat problem with whatever i need to do..''

I'll share my personal experience with my current gro-cab build. After many problems keeping my 600w water-cooled light in a 2'x3'x6' cabinet, I am now able to keep my cab 1-2 degrees above ambient temperature. I had to hang a 154 CFM 4"duct booster fan in the attic with a duct hose out the top of the cab, through a hole in the ceiling, constantly on. Now my cab is like a giant reflector hood. Works great but I can't add CO2 the way things are. I'm hypothesizing installing a freezer core to cut down on exhausted air so I can add CO2. Be prepared for a little trial and error. Good luck!

kathleenbilly said:

As it stands with my 400w and 4 inch extraction, the room temperature is 21 c but within the tent it's 39 c !

To be fair i have no inlet fan, i opened the tent and blow and cooling fan direct into it and got temps down to 25 c.


So i'm going to shorten the ducting run of the extraction which should improve that, as it's far too long 3 meters with two 45 degree bends not good.

I've learned i definately need a inlet fan and i will add the ac in the next week or so....''

Lets see if i can get the temps right with my 400w and the big changes above overwise i'm wasting my time with the thought of a 600w but that is my aim i will tackle this heat problem with whatever i need to do..''

Click to expand...

if you can get an inlet fan in there with an exhaust that should take care of the heat poblem.

Couple of month lurker, first time posting. (Hi everyone).

Another thing to consider is $'s. Setting up a cool tube (closed loop or even open ended) that's vented out of the space with a fan that pull's .5 amps is much cheaper than an AC unit that's probably pulling upwards of 10 amps or even more depending on the unit, to do the same amount of cooling. You'd probably save enough money alone in electricity in payback for running a 600W right up against your girlies.

Just a thought.

mygirls said:

if you can get an inlet fan in there with an exhaust that should take care of the heat poblem.

Click to expand...

Looks like you may be right,

I have reduced the length of the extraction exhaust to 1.5 meters taken out the bends so it's completely straight.

To do this I had to cut my own hole in the tent no probs. The extraction improvement on my 4 inch fan has i would say almost doubled the temps inside this tent is 26 c and this is without even an inlet fan just passive air from the bottom vents! that said the outside tent room temp is very cool at only 19 c with the window open.

But i will buy next a 6 inch fan, carbon filter etc and then change the 4 inch fan extraction to then work as the inlet, still running this with my 400w.

I will get my answer as to whether i can get the 600w in there but it's looking good so far i think i'm moving in the right direction.

I will still buy the air con but the above i will do first.